Hey, Drone. sorry that I didn't get back sooner on this. I have not been able to let the engine run very long, as I am still needing to get a fan belt for the waterpump. I DID, however, find my trouble... turns out that the wiring in the rear behind the trim panel had been chewed through by rodents when the Tracker had been parked and left for dead. Jumped the ends together, and, gee, would ya look at that: The gas gauge DOES work. Spliced it together, checked again, and is now g2g, pending fanbelt. Thanks for the help, though. I did, somehow, manage to break the temp sensor "tab" while messing with things...
$14 bucks later, I have a new sensor to install tonight.